CC not installing - Mac

Hi. I've been scouring the web but I can't make custom content/mods work for me.

Info:
Computer: MacBook Air
- Custom Content and Script Mods buttons are both ON and I have tried turning them off and on again.
- no mods show up in the list of CC/Mods you can access through the options menu
- no mods show up in CAS or Build mode
- I put all .package files in Electronic Arts/Sims4/Mods
- there are NO .rar or .zip files in the Mods folder
- there are NO subfolders after Mods
- laptop mode is OFF
- have tried removing the Mods folder to regenerate multiple times, no luck
- have tried editing resource.cfg, no luck
- thinking maybe the cc I downloaded was bad, I downloaded a new one to try, but that one doesn't show up either.

I'm afraid to do much else on my own because when I removed the Mods folder last time, the game sent me an error message saying it was missing info and couldn't be played. I fixed it easily by putting the Mods folder back, but I have no idea why that happened.

One thing that I'm considering could somehow be an issue... my sims game is all on an external hard drive. I don't know why that would be an issue, but I thought I'd mention it.

As for the Mods folder, it was weird. I didn't remove anything else. However, when I move it to the desktop, what it actually does on my computer is make a copy for the desktop and leave the original in the game. So after doing that, I had to manually delete the Mods file from the game, but then the game didn't regenerate a new one and just told me it was missing information until I put the Mods folder back.